To handle data transport disruptions, existing systems for providing audio conversation over unreliable transmission media use packet loss mitigation (PLM) techniques that manipulate audio to correct for packet loss or delay. These techniques are appropriate and necessary when used in moderation. However, when overused they can degrade the quality of the audio below the level of intelligibility.
Examples of PLM Techniques:                Interpolation—Replace missing portions of audio with interpolated audio. When interpolation is done to excess, the result can be audio that resembles normal speech but really is not.        Slowing down—Replace missing portions of audio with slowed-down audio taken from before or after the missing portion.        Speeding up—Speed up delayed audio to lower the transmission delay.        Changing codecs—Lower the demands on network bandwidth by changing the parameters of the audio codec in use or by switching to a different codec to lower the data rate.        Forward Error Correction—Replicate audio data redundantly in the transmission.        
In existing systems, the user experiences unintelligible or missing audio when sufficient data is not delivered over the network in a timely fashion. Importantly, the user has trouble knowing when whole portions of the conversation have been lost. The transmitting user has no way of knowing when his speech has been delivered unintelligibly or not at all, and the listening user often has no way of knowing that some of what he or she should have heard has been deleted by the system. Furthermore, a call can be dropped altogether, and the transmitting user doesn't become aware for quite a long time that everything he said was deleted. Users often are forced to try to unravel the resulting miscommunication, compounding the problems.